Navassa Island, Fr. Navasse, coral and limestone islet, c.1 sq mi (2.6 sq km), in the Caribbean Sea between Haiti and Jamaica. Located c.100 mi (160 km) S of the U.S. naval base at Guantanamo Bay, Cuba, the uninhabited island is an unincorporated American territory. Claimed by the United States in 1857, Navassa was the site of a guano-mining operation (1865-98) and a coast guard lighthouse (1917-96). An area of great biodiversity, the island is now a wildlife refuge.